Scanning systems have one or both functions of viewing objects and reproducing images of the objects on a medium. "Scanning" refers to the typical point-by-point method by which an object is viewed or an image is reproduced. An example of a scanning system which is used to "read" or view a restricted range of objects is the bar code reader which is often found in retail merchandising stores. With the sale of an item of merchandise, the reader is passed over a pattern of bars, the "object," attached to the item for a nearly instantaneous access of price information and an update of sales and inventory information.
An example of scanning system which is used to reproduce images is television. A television set uses a raster scan technique for creating images on the screen of a cathode ray tube.
The present invention is directed toward a scanning imaging system, i.e., a system by which an object is viewed by the system and an image is created by scanning. In general, the organization of a scanning imaging system has a radiation source element which directs radiation toward the viewed object, a detector element which receives the radiation reflected by the object and converts the radiation into electrical signals, an element for processing the electrical signals, and an imaging element for converting the processed signals into an reproduced image of the object.
Heretofore, scanning imaging systems have had different combinations of a detector element scanning the object with a source of radiation to perform the viewing function. Such combinations have included a detector element scanning with the radiation source element fixed with respect to the object or even with the radiation source element completely eliminated (where, for example, ambient light is used in place of the radiation source), or the detector element fixed and the radiation source element performing the scanning function.
In these systems the radiation source element, the detector element, and the reproduction element are treated as separate units of the system. In a few instances, the viewing elements (the source element and detector element) have been combined into one scanning unit, such as in the case of a bar code reader discussed above. However, the need for highly compact and integrated scanning imaging systems remains largely unsatisfied.
The present invention satisfies this need for a scanning imaging system which is not only compact, but also easily manufacturable and thus low in cost, high in performance with low power requirements. The present invention has the further benefit of being able to perform the viewing and reproduction functions simultaneously or separately as is required.